As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE FLIGHT FROM OAIX TO OASH THE NR 1 ENG FIRE WARNING LIGHT ILLUMINATED. THE EMERGENCY CHECKLIST WAS ACCOMPLISHED & A RETURN TO OAIX WAS ACCOMPLISHED WITHOUT INCIDENT. FOUND FIRE LOOP CHAFFING ENG DECK, REPOSITIONED LOOP ACCOMPLISHED IAW S61N MM CH 26-10-2.